Object Name: string-gnomon sundial
Dimensions: closed: 1.2 x 3.3 x 5.2 cm (1/2 x 1 5/16 x 2 1/16 in.)
open: 4.4 x 3.3 x 5.2 cm (1 3/4 x 1 5/16 x 2 1/16 in.)
Description: This portable, horizontal string-gnomon sundial is designed for a latitude of 48° and is fashioned of silver and gilt brass in diptych form. The gilding is very worn.
This face has a circular table showing the length of daylight and the date that the sun enters each zodiacal sign during a given month of the year. From the outside in towards the center, each concentric circle shows: "Tabula longitudinis diei et ingresu: sol: in 12 signa zodiaci;" "DIES MENS" with civil calendar dates; "MENSES" with names of months in Latin abbreviations; "HORA" with the hours of daylight on the dates in the second circle above; "SIGNA" with the Latin name of the zodiacal sign in abbreviated form; "DIES" with the civil calendar date that the sun enters the sign above; "ELEVACIO POLI 48 GRAD;" and blank. (The vernal equinox is on March 10.) The corners of leaf 1a are ornamented with engraved leaves. The edges have a wavy decoration. The front edge (opposite the hinged edge) has a fixed hook which keeps the sundial closed when it locks around a suspension ring on leaf 2b.
Lunar volvelle for finding the phases of the moon or using the sundial as a moondial. "SEPTENTRIO" and "MERIDIES" are at the top and bottom of the outer circle. Within this, engraved on the gilt brass surface, are the hours, 1-12 twice by 1/4 hours, in a clockwise direction. On the silvered volvelle are the hours 3-12-9, by 1/4 hours, clockwise, with the gap in hours cut away to create a pointer to a scale below reading the age of the moon, 1-29 1/2. Continuing towards the center of the silver volvelle, there is a circular aperture to reveal the lunar phase; and an aspectarium.
A horizontal string-gnomon dial with a gilt brass plumb bob and hinged bracket supporting the northern end of the string. The silvered hour scale has hours 4-12-8, by 1 hour units, engraved on a scroll. There is a sun face at teh base of the gnomon. The magnetic compass has a wind rose of four points marked with Latin abbreviations. There is an arrow shaped like a contemporary compass needle to indicate magnetic declination at approximately 10°E . The compass needle is a modern replacement of the blue-silver diamond form. Glass is present.
This leaf has geometric and leafy decorations. The side edges of the leaf have scrollwrok decorations. The front edge of leaf 2a has a suspension ring.
Function: Time finding at one latitude after orienting the gnomon to point toward true North.
Curatorial Remarks: Appraisal by Brieux, 9/24/01: $ 3000. Attributed to Ulrich Schniep by Sara Shechner. See Zinner, Figure 31-2 for a similar instrument.